Technical Field
The present invention relates generally to arginine deiminase (ADI) proteins, including ADI proteins having reduced cross-reactivity with ADI-PEG 20 antibodies. Such ADI proteins are useful for treating arginine-dependent or related diseases such as cancer.
Description of the Related Art
Amino acid deprivation therapy can be an effective treatment of some forms of cancer. To date, there is one known clinical example relevant to this approach which utilizes asparaginase to lower circulating levels of asparagine and inhibit protein synthesis. This treatment is particularly effective for acute lymphoblastic leukemia (Avramis 2005, Viera Pinheiro 2004). Acute lymphoblastic leukemia cells require the amino acid asparagine for growth and proliferation. In contrast, most normal human cells are capable of synthesizing asparagine and are unaffected by asparagine depletion. Therefore, decreasing serum asparagine with asparaginase can selectively kill the cancer cells without harming the normal cells, tissues, and host. An E. coli derived form of asparaginase has been approved for human use. However, asparaginase is found only in microbes; which makes it highly immunogenic in humans and also has a short serum half-life following injection (Avramis 2005). To make asparaginase a more effective drug, these drawbacks were minimized by formulating the E. coli derived asparaginase with polyethylene glycol (PEG) to reduce the immunogenicity of this enzyme and the associated allergic reactions. In addition, PEG greatly prolongs the circulating half-life of asparaginase, which reduces both the frequency of treatment and the total cost of the therapy. PEG formulated asparaginase is approved for use and is marketed under the trade name Oncaspar® (Oncaspar® 2011, Avramis 2005, Viera Pinheiro 2004, Fu 2007, Zeidan 2008).
Arginine is another non-essential amino acid for humans and mice (for review see Rogers 1994). In humans, arginine can be synthesized from citrulline in two steps via the Krebs (urea) cycle enzymes argininosuccinate synthetase (ASS, L-citrulline:L-aspartate ligase [AMP-forming], EC 6.3.4.5) and argininosuccinate lyase (ASL, L-argininosuccinate arginine-lyase, EC 4.3.2.) (Haines 2011, Wu 2009, Morris 2006, Husson 2003, Tapiero 2002, Rogers 1994). ASS catalyzes the conversion of citrulline and aspartic acid to argininosuccinate, which is then converted to arginine and fumaric acid by ASL. An arginine deficient diet in humans does not evoke hyperammonemia, orotic aciduria, nor alter the rate of whole body nitric oxide (NO) synthesis in adult humans (Tapiero 2002, Castillo 1995, Rogers 1994, Carey 1987, Barbul 1986, Snyderman 1959, Rose 1949). Although preterm infants appear to require arginine (Wu 2004), arginine levels do not correlate with age among infants, children and young adults (Lücke 2007). In 1992, Takaku and Sugimura separately reported that human melanomas and hepatocellular carcinoma (HCC) cell lines appear to require arginine for growth. Other studies showed that pegylated ADI was effective for the treatment of melanomas and hepatomas with few adverse effects.
ADI-PEG 20 treatment requires multiple doses over a period of time. After a number of treatments, anti-ADI-PEG 20 antibodies can develop that may limit its continued effectiveness. Therefore, there is a need in the art for ADI that has reduced cross-reactivity to anti-ADI-PEG20 antibodies for use in treatment in order to improve and extend the efficacy of arginine depletion therapy. The present invention provides this and other advantages for the treatment of cancers.
References: Avramis V I, Panosyan E H. 2005. Clin Pharmacokinet 44:367-393; Barbul A. 1986. J Parenteral Enteral Nutr 10:227-238; Carey G P, et al. 1987. J Nutr 117:1734-1739; Castillo L, et al. 1995. Am J Physiol 268 (Endocrinol Metab 31):E360-367; Fu C H, Sakamoto K M. 2007. Expert Opin Pharmacother 8:1977-1984; Haines R J, et al. 2011. Int J Biochem Mol Biol 2:8-23; Husson A, et al. 2003. Eur J Biochem 270:1887-1899; Lücke T, et al. 2007. Clin Chem Lab Med 45:1525-1530; Morris S M Jr. 2006. Am J Clin Nutr 83(Suppl):5985-5125; Rogers Q R. 1994. In Proceedings from a Symposium Honoring Willard J. Visek—from Ammonia to Cancer and Gene Expression. Special Publication 86—April, 1994, Agriculture Experiment Station, University of Illinois, 211 Mumford Hall, Urbana, Ill. 61801, pp. 9-21; Tapiero H, et al. 2002. Biomed Pharmacother 56:439-445, 2002; Viera Pinheiro J P, Boos J. 2004. Br J Haematol 125: 117-127; Wu G, et al. 2009. Amino Acids 37:153-168; Wu G, et al. 2004. J Nutr Biochem 15:442-451; Zeidan A, et al. 2008. Expert Opin Biol Ther 9:111-119).